1. Web Security Academy
  2. JWT attacks
  3. Lab

Lab: JWT authentication bypass via flawed signature verification


This lab uses a JWT-based mechanism for handling sessions. The server is insecurely configured to accept unsigned JWTs.

To solve the lab, modify your session token to gain access to the admin panel at /admin, then delete the user carlos.

You can log in to your own account using the following credentials: wiener:peter


We recommend familiarizing yourself with how to work with JWTs in Burp Suite before attempting this lab.

Register for free to track your learning progress

The benefits of working through PortSwigger's Web Security Academy
  • Practise exploiting vulnerabilities on realistic targets.

  • Record your progression from Apprentice to Expert.

  • See where you rank in our Hall of Fame.

Already got an account? Login here